ABSTRACT
The increases in both the rate and number of multiple births in the United States and elsewhere have been well documented in the literature and are described in detail in this book1-7. Several factors underlie the ascending incidence of multiple births in the USA, including the rapid growth in the use of assisted reproductive technologies (ART), the noticeable rise in the average age of women giving birth to their first child and the resultant and marked change in the distribution of the age of mothers at time of delivery8-10. Not only do older mothers have a greater likelihood of spontaneous multiple births, but also the necessity for employing ART increases as maternal age advances because of the accumulation of conditions that predispose to infertility8-10.
